La-Nina-PatternBy David Downey
ddowney@pe.com @PE_DavidDowney on Twitter
As if drought-stricken Southern California’s El Niño bust wasn’t bad enough, now the experts say we’re headed for a bona fide period of bone-dry weather. La Niña beckons.
“La Niña is the diva of drought, which is not what we want to see,” said Bill Patzert, climate scientist at NASA’s Jet Propulsion Laboratory in Pasadena. “We got a little relief, but we’re still in a drought. And we don’t want to go deeper into this drought.”
So it wasn’t exactly welcome news when the National Oceanic and Atmospheric Administration’s Climate Prediction Center declared Thursday there is a good chance the dark side of the wet-weather force will seize the skies over Southern California.
The climate center predicts El Niño will stick around a couple more months, giving way to La Niña by fall. The center says there’s a 70 percent chance of that happening.
El Niño is a weather phenomenon that arrives once every several years. Its signature is a large pool of abnormally warm water in the equatorial Pacific that often fuels wet winters in the southern U.S., including Southern California.
Perhaps the most famous one occurred in winter 1997-98, when 30 inches of rain fell on much of Southern California. Something like that was widely anticipated this season. It didn’t happen, of course. And the season is rapidly drawing to a close.
La Niña is the opposite: It’s characterized by unusually cool ocean water and typically delivers drierthan- normal winters.
The influential ocean and atmospheric condition “is kind of a reverse of what we see” in El Niño, said Mike Halpert, deputy director of the climate center.
Forest die-off
The alarming thing about the prospect, said Richard Minnich, a UC Riverside earth sciences professor, is that La Niña could turn a four-year drought into one twice as long.
Minnich said the big 1997-98 El Niño was followed by four dry years, including one of the driest in history. That triggered an unprecedented die-off of pine trees in the Southern California’s mountains.
“That’s an example of what could happen,” he said.
Minnich said the good news is that, because of El Niño-fueled downpours last summer and the dumping of several feet of snow in early January, forests are in reasonably good shape.
“The trees will get through this summer, and we won’t have a massive die-off,” he said.
Minnich cautioned it’s important to keep the global forecast in perspective.
“What is easy to predict is that there will be a La Niña,” Minnich said. “What is not easy to predict is the magnitude of it.”
Just as predictions of heavy El Niño rains turned out wrong, so could the La Niña forecast, he said.
Comeback possible?
“You can’t predict this stuff. It’s just probabilities,” Minnich said. “The oods are about 7 in 10 that it will be a dry year next year.”
If there is something to be learned from the puzzling El Niño experience, Patzert said, it is that one can get into trouble when “you play the odds.”
“Most Godzilla El Niños do result in soaking,” Patzert said. “So what did we learn from that? Mark Twain said, ‘It ain’t what you don’t know that gets you in trouble, it’s what you know for sure that just ain’t so.’ “The bottom line here is, be careful with statistics or with what normally would be expected. What I learned this winter is that normal is a cycle on a washing machine.”
The Associated Press contributed to this report.

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